Field of the Invention
The invention is directed to electromedical implants for measuring, and for delivering electric pulses, or, for example, as an implantable central unit for wireless signal transmission between multiple implants, and to the optimized composition of such implants.
Description of the Background Art
Electromedical implants for measuring electrical potentials and for delivering electric pulses have been used for decades in human and animal bodies for measuring electrical potentials caused by neural activity. Implants used to electrically stimulate neural structures have also been known for quite some time. Disrupted and/or inadequate intrinsic (the body's own) neural activity or stimulus conduction is a typical indication of the need for such an implant. Various measuring and/or stimulation devices exist, which differ in terms of the shape and design, depending on the technical properties and the area of application of the nervous system.
Systems for spinal cord stimulation are used, for example, when neural structures for the functionality of the extremities were damaged and are then used, in general, for pain therapy or to support rehabilitation. Such implants are composed of a device assembly and different electrode leads, for example. The device assembly comprises the device electronics, which include electric circuit arrangements, for example, for measuring and analyzing the electrical potentials and for controlling the electrical stimulation. The device assembly typically also comprises an energy source for the implant, such as a battery, and electrical terminals for the electrode lead. Known electrode leads for such purposes have an elongated lead body, one or more electrodes at the distal end of the lead, and an electrical contact at the proximal end of the lead, by way of which they can be connected to the electrical terminals of the device assembly. During the implantation process, the device assembly is subcutaneously introduced beneath the patient's skin in a suitable location, while the electrode leads are implanted in locations suitable for measuring and stimulating the nerve tissue and are connected to the device assembly.
Known systems for stimulating the heart have a similar composition as the described spinal cord stimulation system. Common cardiac pacemaker systems, implantable cardiac defibrillators or systems used for cardiac resynchronization (cardiac rhythm therapy (CRT) systems) are also typically composed of a device assembly and electrode leads. To measure and stimulate the right half of the heart, electrode leads are advanced via the superior vena cava into the right atrium and right ventricle of the heart and anchored at the desired implantation site. Electrode leads for measuring and stimulating the left half of the heart are typically positioned in a branch of the coronary sinus. The device assembly of such a cardiac stimulator is subcutaneously embedded in the patient's collarbone region and connected to the electrode lead.
Cardiac pacemaker systems that are not equipped with above-described electrode leads are known in the prior art. Such cardiac pacemaker systems are also referred to as ‘leadless’ systems, or more precisely ‘leadless pacemakers.’ Such systems comprise a device assembly in which the electrodes for measuring and stimulation are localized on the housing. The device assembly is implanted directly in the atrium or in the ventricle of the heart by way of a catheter system and fixed there.
Furthermore, implantable pure monitoring devices for the heart are known. These are positioned subcutaneously and do not comprise electrode leads that are implanted intracardially. Such devices comprise measuring electrodes on the device housing, which are used to pick up electrical potentials, for example so as to filter out heart signals.
More precisely, known compositions of the aforementioned leadless systems and pure monitoring devices are such that these have a device housing in which the housing electronics and energy supply system are accommodated. Within the housing, the housing electronics and energy supply system are electrically connected to one another via an electrical feedthrough. Furthermore, such a typical composition provides for the device electronics to be connected to a measuring electrode via a further electrical feedthrough. The housing is electrically coupled to the second electrode pole for electrical measurement and/or electrical stimulation and is thus used as a counter pole to the measuring electrode.
An implantable medical device is proposed in US 2015/0073507 A1, for example, wherein the medical device comprises at least two electrodes which are coupled to the device housing.
The previously known leadless systems, implantable monitoring devices and general implantable electromedical devices, and in particular the latter without electrode leads, have a relative complex device composition, such as comprising electrical feedthroughs and separate antennas.
For the described leadless systems, implantable monitoring devices and, in general, for implantable electromedical devices, and in particular the latter without electrode leads, it is advantageous to miniaturize the device composition or device housing.